FIG. 1 schematically illustrates a USB Type-C interface 100. The USB Type-C interface 100 is a USB Type-C receptacle. The pins of the USB Type-C receptacle 100 comprise A group pins (A1˜A12) and B group pins (B1˜B12). The A1 pin, the A12 pin, the B1 pin and the B12 pin are ground voltage pins (GND); the A4 pin, the A9 pin, the B4 pin and the B9 pin are bus voltage pins (Vbus); the A2 pin and the A3 pin are a first transmitting differential pair (TX1+ and TX1); the B2 pin and the B3 pin are a second transmitting differential pair (TX2+ and TX2−); the B10 pin and the B11 pin are a first receiving differential pair (RX1+ and RX1−); the A10 pin and the A11 pin are a second receiving differential pair (RX2+ and RX2−); the A6 pin and the A7 pin are a USB 2.0 data differential pair (D+ and D−); the B6 pin and the B7 pin are also a USB 2.0 data differential pair (D+ and D−); the A5 pin and the B5 pin are configuration channel pins (CC1 and CC2); and the A8 and B8 are reserved pins (SBU1 and SBU2).
Moreover, the first transmitting differential pair (TX1+ and TX1), the second transmitting differential pair (TX2+ and TX2−), the first receiving differential pair (RX1+ and RX1−) and the second receiving differential pair (RX2+ and RX2−) are capable of carrying USB 3.1 differential signals.
As shown in FIG. 1, A group pins (A1˜A12) and B group pins of the USB Type-C receptacle 100 are symmetrical. When a USB device is plugged into the USB Type-C receptacle 100 in an up orientation or a down orientation, the USB device can normally work. For example, when the USB device is plugged into the USB Type-C receptacle 100 in the up orientation, the USB device is connected with the A group pins, and the USB Type-C receptacle 100 is in communication with the USB device through the A group pins. On the other hand, when the USB device is plugged into the USB Type-C receptacle 100 in the down orientation, the USB device is connected with the B group pins, and the USB Type-C receptacle 100 is in communication with the USB device through the B group pins.
Furthermore, the USB Type-C interface can be used as the connection interface of other device such as a power device, a data device or a display device. For example, when the display device with PCIe interface is plugged into the USB Type-C receptacle, PCIe interface signals can be transmitted through the pins of the USB Type-C receptacle. This is the concept of PCIe over USB.